U.S. patent application number 14/351718 was filed with the patent office on 2014-10-23 for long patterned alignment film, and long patterned retardation film using same.
This patent application is currently assigned to DAI NIPPON PRINTING CO., LTD.. The applicant listed for this patent is Masanori Fukuda, Keiji Kashima, Hiroyuki Nishimura, Yuugo Noritake. Invention is credited to Masanori Fukuda, Keiji Kashima, Hiroyuki Nishimura, Yuugo Noritake.
Application Number | 20140313581 14/351718 |
Document ID | / |
Family ID | 47180751 |
Filed Date | 2014-10-23 |
United States Patent
Application |
20140313581 |
Kind Code |
A1 |
Kashima; Keiji ; et
al. |
October 23, 2014 |
LONG PATTERNED ALIGNMENT FILM, AND LONG PATTERNED RETARDATION FILM
USING SAME
Abstract
A long patterned alignment film is provided, from which a large
number of patterned retardation films can easily be produced,
having an alignment layer which is in a long form and comprises an
optical alignment material, wherein the alignment layer includes a
first alignment region for causing a rodlike compound having a
refractive index anisotropy to be arranged in a certain direction,
and a second alignment region for causing the rodlike compound to
be arranged in a direction different from the certain direction of
the first alignment region.
Inventors: |
Kashima; Keiji; (Tokyo-to,
JP) ; Nishimura; Hiroyuki; (Tokyo-to, JP) ;
Fukuda; Masanori; (Tokyo-to, JP) ; Noritake;
Yuugo; (Tokyo-to, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kashima; Keiji
Nishimura; Hiroyuki
Fukuda; Masanori
Noritake; Yuugo |
Tokyo-to
Tokyo-to
Tokyo-to
Tokyo-to |
|
JP
JP
JP
JP |
|
|
Assignee: |
DAI NIPPON PRINTING CO.,
LTD.
Tokyo-to
JP
|
Family ID: |
47180751 |
Appl. No.: |
14/351718 |
Filed: |
September 13, 2012 |
PCT Filed: |
September 13, 2012 |
PCT NO: |
PCT/JP2012/073507 |
371 Date: |
April 14, 2014 |
Current U.S.
Class: |
359/489.07 ;
359/601; 428/1.2 |
Current CPC
Class: |
G02B 30/25 20200101;
C09K 2323/02 20200801; Y10T 428/1005 20150115; G02B 1/11 20130101;
G02F 1/133711 20130101; G02B 5/3016 20130101; G02B 1/10 20130101;
G02B 5/3083 20130101 |
Class at
Publication: |
359/489.07 ;
359/601; 428/1.2 |
International
Class: |
G02F 1/1337 20060101
G02F001/1337; G02B 1/10 20060101 G02B001/10; G02B 1/11 20060101
G02B001/11; G02B 5/30 20060101 G02B005/30 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 1, 2012 |
JP |
2012-045433 |
Claims
1-12. (canceled)
13. A long patterned alignment film, comprising an alignment layer
which is in a long form and comprises an optical alignment
material, wherein the alignment layer comprises a first alignment
region for causing a rodlike compound having a refractive index
anisotropy to be arranged in a certain direction, and a second
alignment region for causing the rodlike compound to be arranged in
a direction different from the certain direction of the first
alignment region.
14. The long patterned alignment film according to claim 13,
wherein the alignment layer has a nonalignment region between the
first alignment region and the second alignment region when viewed
in plane.
15. The long patterned alignment film according to claim 13,
wherein the first alignment region and the second alignment region
are formed into a pattern in a form of bands parallel to each other
in a longitudinal direction of the alignment film.
16. The long patterned alignment film according to of claim 13,
wherein the respective directions along which the rodlike compound
is caused to be arranged in the first alignment region and the
second alignment region are different from each other by
90.degree..
17. The long patterned alignment film according to claim 16,
wherein the respective directions along which the rodlike compound
is caused to be arranged in the first alignment region and the
second alignment region are a direction having an angle of
0.degree. to a longitudinal direction and a direction having an
angle of 90.degree. to the longitudinal direction,
respectively.
18. The long patterned alignment film according to claim 16,
wherein the respective directions along which the rodlike compound
is caused to be arranged in the first alignment region and the
second alignment region are a direction having an angle of
45.degree. to a longitudinal direction and a direction having an
angle of 135.degree. to the longitudinal direction,
respectively.
19. The long patterned alignment film according to claim 13,
wherein a transparent film substrate is formed on the alignment
layer.
20. The long patterned alignment film according to claim 19,
wherein an antireflective layer and/or an antiglare layer is/are
formed on a surface of the transparent film substrate that is
opposite to a surface on which the alignment layer is formed.
21. A long patterned retardation film, comprising: the long
patterned alignment film recited in claim 13; and a retardation
layer formed on the alignment layer of the long patterned alignment
film, and comprising a rodlike compound which has a refractive
index anisotropy.
22. The long patterned retardation film according to claim 21,
wherein the alignment layer has a pattern in which the first
alignment region, a non-alignment region and the second alignment
region are, in this order, arranged or repeated one or more times
when viewed in plane, and the retardation layer has a pattern in
which a first retardation region positioned just on the first
alignment region, a buffer region positioned just on the
non-alignment region, and a second retardation region positioned
just on the second alignment region are, in this order, arranged or
repeated one or more times when viewed in plane.
23. The long patterned retardation film according to claim 21,
wherein an in-plane retardation value of the retardation layer
corresponds to .lamda./4.
24. The long patterned retardation film according to claim 21,
wherein an adhesive layer and a separator are, in this order,
formed on the retardation layer.
Description
TECHNICAL FIELD
[0001] The present invention relates to a long patterned alignment
film from which a large number of patterned retardation films can
be easily produced.
BACKGROUND ART
[0002] As flat panel displays, two-dimensional displaying type
displays have hitherto been in the main current. In recent years,
however, flat panel displays capable of attaining three-dimensional
displays have been coming to public notice. Such known displays
have partially been commercially available. Future flat panel
displays have a tendency of being naturally required to have the
ability of attaining three-dimensional displays. Thus, in various
fields, studies have been advanced about flat panel displays
capable of attaining three-dimensional displays.
[0003] In order to cause a flat panel display to attain
three-dimensional displays, it is usually necessary to display, for
any viewer, an image for his/her right eye and an image for his/her
left eye separately from each other in some mode. As a method for
displaying an image for the right eye and an image for the left eye
separately from each other, for example, a passive mode is known.
With reference to a figure, the three-dimensional display mode of
the passive mode is described. FIG. 19 is a schematic view
illustrating an example of passive mode three-dimensional display.
As illustrated in FIG. 19, in this mode, pixels constituting a flat
panel display are initially divided patternwise into two-type
pixels, that is, image-displaying pixels for the right eye and
image-displaying pixels for the left eyes. In the pixels in one of
the two groups, an image for the right eye is displayed while in
those in the other group, an image for the left eye is displayed.
The image for the right eye and that for the left eye are converted
into circularly polarized light rays orthogonal to each other by
use of a linearly polarizing plate, and a patterned retardation
film in which a patterned retardation layer corresponding to the
pattern of the division of the pixels is formed. Furthermore, any
viewer is let to put circularly polarizing glasses on, in which
circularly polarizing lenses for generating circularly polarized
rays orthogonal to each other are adopted as a lens for the right
eye and a lens for the left eye. Thus, the image for the right eye
is passed through only the lens for the right eye while the image
for the left eye is passed through only the lens for the left eye.
In this way, the image for the right eye reaches only viewer's
right eye while the image for the left eye reaches only viewer's
left eye. A mode that any three-dimensional display can be attained
in this way is the passive mode.
[0004] The passive mode has an advantage that three-dimensional
displays can easily be attained by the use of a patterned
retardation film as described above and circularly polarizing
glasses matched therewith.
[0005] As described above, in the passive mode, it is essential to
use a patterned retardation film. However, about such patterned
retardation films, broad researches and developments have not yet
been made so that standard techniques thereof have not been
established in the present circumstances. In connection therewith,
Patent Literature 1 discloses, as a patterned retardation film, a
patterned retardation plate comprising a glass substrate, a photo
alignment layer thereon in which alignment regulating force is
patternwise controlled, and a retardation layer formed on the photo
alignment layer and containing a liquid crystal compound the
arrangement of which is patterned correspondingly to the pattern of
the photo alignment layer. However, it is essential to use a glass
plate in such a patterned retardation plate as disclosed in Patent
Literature 1. Thus, the retardation plate is expensive. Moreover,
the technique disclosed therein does not make it possible to
produce a large number of retardation plates each having a large
area. Consequently, it is difficult to put the technique into
practical use.
[0006] For such reasons, patterned retardation films having
practicability have still been at the stage of research and
development, and almost all thereof have not been known as popular
articles. As a result, there remains a problem that display devices
have not been gained which can be produced in large number at low
costs by a simple method, and can display three-dimensional
images.
CITATION LIST
Patent Literature
[0007] Patent Literature 1: Japanese Patent Application Publication
(JP-A) No. 2005-049865
SUMMARY OF INVENTION
Technical Problem
[0008] The present invention has been made in light of such
situations, and a main object thereof is to provide a long
patterned alignment film from which a large number of patterned
retardation films can easily be produced.
Solution to Problem
[0009] In order to solve the above-mentioned problems, the present
invention provides a long patterned alignment film, comprising an
alignment layer which is in a long form and comprises an optical
alignment material, wherein the alignment layer comprises a first
alignment region for causing a rodlike compound having a refractive
index anisotropy to be arranged in a certain direction, and a
second alignment region for causing the rodlike compound to be
arranged in a direction different from the certain direction of the
first alignment region.
[0010] According to the invention, the long patterned alignment
film has the first and second alignment regions, and this matter
makes it possible that by action of applying the rodlike compound
thereto, a retardation layer is easily formed which has a first
retardation region and a second retardation region in which the
respective arranging directions of the rodlike compound are
different from each other.
[0011] Moreover, the patterned alignment film is in a long form,
and this form makes it possible to form easily a long patterned
retardation film from which a large number of patterned retardation
films can be produced. Furthermore, the long form makes it possible
to make the flexibility of the production process high.
[0012] In the invention, it is preferred that the first alignment
region and the second alignment region are formed into a pattern in
the form of bands parallel to each other in the longitudinal
direction of the alignment film.
[0013] This matter makes it easy to cause the pattern in which the
first and second retardation regions are formed to have a
relationship corresponding to a pattern in which pixels are formed
in a color filter or some other used in a display device. This also
makes it possible to produce a large number of patterned
retardation films easily by the following: preparing the long
alignment layer wound into a roll form; feeding the long alignment
film while the long alignment layer wound in the roll form is
unwound; and then feeding the film continuously while the film is
irradiated with polarized ultraviolet rays.
[0014] In the invention, it is preferred that the respective
directions along which the rodlike compound is caused to be
arranged in the first alignment region and the second alignment
region are different from each other by 90.degree.. When a
retardation layer is formed on this patterned alignment film, the
first retardation region and the second retardation region
contained in the retardation layer can be caused to have a
relationship that their directions each giving the largest
refractive index (slow axis directions) are orthogonal to each
other. Thus, the long patterned alignment film of the invention can
be more favorably used to produce 3D display devices.
[0015] In the invention, it is preferred that: the respective
directions along which the rodlike compound is caused to be
arranged in the first alignment region and the second alignment
region are a direction having an angle of 0.degree. to the
longitudinal direction and a direction having an angle of
90.degree. to the longitudinal direction, respectively; or the
respective directions along which the rodlike compound is caused to
be arranged in the first alignment region and the second alignment
region are a direction having an angle of 45.degree. to the
longitudinal direction and a direction having an angle of
135.degree. to the longitudinal direction, respectively.
[0016] When the rodlike compound has the former arranging
direction, the long patterned alignment film of the invention can
be rendered a film usable suitably for, for example, 3D liquid
crystal display devices in a TN mode.
[0017] When the rodlike compound has the latter arranging
direction, the long patterned alignment film of the invention can
be rendered a film usable suitably for, for example, 3D liquid
crystal display devices in a VA or IPS mode.
[0018] In the invention, it is preferred that a transparent film
substrate is formed on the alignment layer. This matter makes it
possible to make the formation of the alignment layer easy.
[0019] In the invention, it is preferred that an antireflective
layer and/or an antiglare layer is/are formed on a surface of the
transparent film substrate that is opposite to the surface on which
the alignment layer is formed. When a display device is produced,
this matter makes it possible to form a patterned retardation film
capable of giving a display device good in display quality.
[0020] The invention provides a long patterned retardation film
comprising the above-mentioned long patterned alignment film, and a
retardation layer formed on the alignment layer of the long
patterned alignment film and comprising a rodlike compound having a
refractive index anisotropy.
[0021] According to the invention, the long patterned retardation
film has the above-mentioned long patterned alignment film, and
this matter makes it possible to render this long patterned
retardation film a film having a first retardation region and a
second retardation region in which the respective arranging
directions of the rodlike compound are different from each
other.
[0022] It is therefore possible to form easily a large number of
patterned retardation films applicable to three-dimensional display
devices.
[0023] Moreover, the long patterned retardation film is long, and
thus the production process of the patterned retardation film can
be made high in flexibility.
[0024] In the invention, it is preferred that the in-plane
retardation value of the retardation layer corresponds to
.lamda./4. This matter makes it possible to convert respective
linearly polarized light rays passing through the first and second
retardation regions to circularly polarized light rays orthogonal
to each other. Thus, when the in-plane retardation value of the
retardation layer corresponds to .lamda./4, the long patterned
retardation film of the invention can be rendered a film usable
more suitably for producing 3D display devices.
[0025] In the invention, it is preferred that an adhesive layer and
a separator are, in this order, formed on the retardation layer.
This matter makes it possible to bond the long patterned
retardation film of the invention easily onto a different
member.
Advantageous Effects of Invention
[0026] The long patterned alignment film of the invention produces
an advantageous effect of making it possible to produce a large
number of patterned retardation films easily.
BRIEF DESCRIPTION OF DRAWINGS
[0027] FIG. 1 is a sectional view taken on line A-A in FIG. 2.
[0028] FIG. 2 is a schematic plan view illustrating an example of
the long patterned alignment film of the present invention.
[0029] FIG. 3 is a schematic plan view illustrating another example
of the long patterned alignment film of the invention.
[0030] FIG. 4 is a schematic sectional view illustrating still
another example of the long patterned alignment film of the
invention.
[0031] FIGS. 5A to 5D are a process chart illustrating an example
of a method for producing the long patterned alignment film of the
invention.
[0032] FIG. 6 is a schematic view illustrating an example of an
apparatus for producing the long patterned alignment film of the
invention.
[0033] FIG. 7 is a schematic view illustrating another example of
the apparatus for producing the long patterned alignment film of
the invention.
[0034] FIGS. 8A to 8C are explanatory views for describing an
exposing step used in the invention.
[0035] FIGS. 9A to 9C are explanatory views for describing the
exposing step used in the invention.
[0036] FIG. 10 is an explanatory view for describing the exposing
step used in the invention.
[0037] FIG. 11 is an explanatory view for describing the exposing
step used in the invention.
[0038] FIGS. 12A to 12D are explanatory views for describing the
exposing step used in the invention.
[0039] FIG. 13 is a sectional view taken on line B-B in FIG.
15.
[0040] FIG. 14 is a perspective view taken on line B-B in FIG.
15.
[0041] FIG. 15 is a schematic plan view illustrating an example of
the long patterned retardation film of the invention.
[0042] FIG. 16 is a schematic sectional view illustrating another
example of the long patterned retardation film of the
invention.
[0043] FIG. 17 is a schematic view illustrating an example of an
apparatus for producing the long patterned retardation film of the
invention.
[0044] FIG. 18 is a schematic view illustrating another example of
the apparatus for producing the long patterned retardation film of
the invention.
[0045] FIG. 19 is a schematic view illustrating an example of a
liquid crystal display device capable of displaying a
three-dimensional image in a passive mode.
DESCRIPTION OF EMBODIMENTS
[0046] The present invention relates to a long patterned alignment
film, and a long patterned retardation film using the long
patterned alignment film.
[0047] Hereinafter, a detailed description will be made about the
long patterned alignment film of the invention, and the long
patterned retardation film thereof.
[0048] A. Long Patterned Alignment Film
[0049] The long patterned alignment film of the invention is
initially described.
[0050] The long patterned alignment film of the invention comprises
an alignment layer which is in a long form and comprising an
optical alignment material, wherein the alignment layer comprises a
first alignment region for causing a rodlike compound having a
refractive index anisotropy to be arranged in a certain direction,
and a second alignment region for causing the rodlike compound to
be arranged in a direction different from the certain direction of
the first alignment region.
[0051] Referring to the drawings, the long patterned alignment film
of the invention is described. FIG. 1 is a sectional view taken on
line A-A in FIG. 2. FIG. 2 is a schematic plan view illustrating an
example of the long patterned alignment film of the invention. As
illustrated in FIGS. 1 and 2, a long patterned alignment film 10 of
the invention comprises a long transparent film substrate 1 and a
long alignment layer 2 formed on the transparent film substrate 1
and containing an optical alignment material. The alignment layer 2
is a layer having first alignment regions 2a for causing a rodlike
compound as defined above to be arranged in a certain direction,
and second alignment regions 2b for causing the rodlike compound to
be arranged in a direction different from the certain direction of
the first alignment region 2a.
[0052] Incidentally, in this example, the first alignment region is
a region having an alignment regulating force for arranging the
rodlike compound in a direction orthogonal to the long direction
(longitudinal direction) of the film while the second alignment
region is a region having an alignment regulating force for
arranging the rodlike compound in a direction parallel to the long
direction (longitudinal direction). The first alignment regions 2a
and the second alignment regions 2b are formed in the form of bands
which are parallel to the long direction (longitudinal direction)
and have a width of W1 and a width of W2, respectively.
[0053] Incidentally, the word "long" or the wording "long form"
denotes, out of shapes each geometrically identical to or
approximately to a rectangular parallelepiped, in particular, any
shape formed to have a length sufficiently larger than the width
and the thickness thereof and further make the thickness
sufficiently smaller than the length and the width. The word or
wording denotes, for example, the form of a band having such a
length that the band-form article can be wound into a roll form.
The length of the long patterned retardation film may be decided at
will in accordance with factors such as a weight thereof permitted
to be set into an apparatus for the production, and others.
Specifically, the length is preferably 10 m or more, more
preferably from 50 m to 5000 m, and in particular preferably from
100 m to 4000 m.
[0054] The length is preferably 10 or more times the width, more
preferably from 50 to 5000 times the width, in particular
preferably from 100 to 4000 times the width. The thickness is
preferably from 1/1000 to 1/1000000 of the width. Specifically,
about the alignment layer, the thickness is preferably from 0.01
.mu.m to 1.0 .mu.m; about the retardation layer, the thickness is
preferably from 0.5 .mu.m to 2 .mu.m; and about the transparent
film substrate, the thickness is preferably from 10 .mu.m to 1000
.mu.m. The ranges make these members excellent in handleability and
others.
[0055] According to the invention, the long patterned alignment
film has the first and second alignment regions, and this matter
makes it possible that by action of applying the rodlike compound
thereto, a retardation layer is easily formed which has a first
retardation region and a second retardation region in which the
respective arranging directions of the rodlike compound are
different from each other.
[0056] Moreover, the patterned alignment film is in a long form,
thereby making it possible that by action of applying the rodlike
compound continuously thereto, a long patterned retardation film is
easily formed from which a large number of patterned retardation
films can be produced. Furthermore, the long form makes it possible
to make the flexibility of the production process of the long
patterned retardation film high. Thus, for example, the long
patterned alignment film can be stored in a roll form, or the long
patterned retardation film be formed through the step of unwinding
the long patterned alignment film from the state that the film is
stored in the roll form.
[0057] The long patterned alignment film of the invention has at
least an alignment layer.
[0058] Hereinafter, constituents of the long patterned alignment
film of the invention will each be described in detail.
[0059] 1. Alignment Layer
[0060] The alignment layer used in the invention is in a long form
and contains an optical alignment material.
[0061] The alignment layer has a function that when a retardation
layer is formed thereon, its rodlike compound is caused to be
arranged. In the alignment layer used in the invention, the first
and second alignment regions detailed above are patternwise formed
on the surface of the alignment layer. Thus, in accordance with the
pattern, the first and second retardation regions detailed above
are patternwise arranged on the retardation layer.
[0062] (1) First and Second Alignment Regions
[0063] The first and second alignment regions formed in the
alignment layer in the invention are each a region having a
function of causing a rodlike compound contained in a retardation
layer to be arranged into one direction. The respective directions
along which the rodlike compound is caused to be arranged are
different from each other. In the invention, the first and second
alignment regions are patternwise formed.
[0064] In the alignment layer in the invention, the pattern in
which the first and second alignment regions are formed may be
appropriately decided in accordance with a use purpose of the long
patterned alignment film of the invention, and other factors. Thus,
the pattern is not particularly limited. Examples of this pattern
include a band-form pattern, a mosaic-form pattern, and a staggered
arrangement pattern. It is particularly preferred in the invention
that the first and second alignment regions are formed into a
pattern in the form of bands parallel to each other. When the first
and second alignment regions are formed in this pattern, the
following is made easy: in the case of using, for example, a
patterned retardation film formed by use of the long patterned
alignment film of the invention to produce a liquid crystal display
device, the pattern in which the first and second alignment regions
are formed is caused to have a relationship corresponding to a
pattern in which pixels are formed in a color filter used in the
liquid crystal display device. For this reason, by the matter that
the first and second alignment regions are formed in the pattern in
the form of the bands parallel to each other, a 3D liquid crystal
display device can easily be produced, using the long patterned
alignment film of the invention. In other words, the long patterned
alignment film of the invention can be used suitably for a 3D
liquid crystal display device.
[0065] Moreover, the matter that the first and second alignment
regions are formed in the pattern in the form of the bands parallel
to each other makes the following easy: in the case of using the
long patterned alignment film of the invention to produce a light
emitting type display device such as a plasma display, an organic
EL or an FED, the pattern in which the first and second alignment
regions are formed is caused to have a relationship corresponding,
through a polarizing plate, to a pattern in which pixel regions are
formed in a light emitting type display in the light emitting type
display device. For this reason, by the matter that the first and
second alignment regions are formed in the pattern in the form of
the bands parallel to each other, a 3D light emitting type display
device can easily be produced, using the long patterned alignment
film of the invention. In other words, the long patterned alignment
film of the invention can be used suitably for a 3D light emitting
type display device. Incidentally, if necessary, a color filter may
be used in the light emitting type display device.
[0066] In the case where the first and second alignment regions are
formed in the pattern in the form of the bands parallel to each
other, specific examples of the case include the above-mentioned
long patterned alignment film illustrated in FIGS. 1 and 2.
[0067] When the first and second alignment regions are formed in a
pattern in the form of bands, the respective widths of the first
and second alignment regions may be equal to or different from each
other. However, it is preferred in the invention that the
respective widths of the first and second alignment regions are
equal to each other. In a color filter used in a liquid crystal
display device, pixel regions including R, G, B and some other are
usually formed to be equal to each other in width. Thus, by making
the respective widths of the above-mentioned first and second
alignment regions equal to each other, the following is made easy:
when the long patterned alignment film of the invention is used to
produce a liquid crystal display device capable of attaining
three-dimensional displays, the pattern in which the first and
second alignment regions are formed is caused to have a
relationship corresponding to a pattern in which pixel regions are
formed in a color filter used in the liquid crystal display device.
As a result, a 3D display device can easily be produced by use of
the long patterned alignment film of the invention. Moreover, pixel
regions used in a light emitting type display device are also
formed to be equal to each other in width. Thus, by making the
respective widths of the above-mentioned first and second alignment
regions equal to each other, the following is made easy: when the
long patterned alignment film of the invention is used to produce a
light emitting type display device capable of attaining
three-dimensional displays, the pattern in which the first and
second alignment regions are formed is caused to have a
relationship corresponding to a pattern in which pixel regions used
in the light emitting type display device are formed. As a result,
a 3D light emitting type liquid crystal display device can easily
be produced by use of the long patterned alignment film of the
invention. When the pattern in which the first and second alignment
regions are formed is positioned to be precisely fitted to a stripe
pattern of the color filter, it is preferred to form the former
pattern and the latter stripe pattern of the color filter to have
widths having a relationship corresponding to each other.
[0068] Specific values of the respective widths of the first and
second alignment regions are appropriately decided in accordance
with a use purpose of the long patterned alignment film of the
invention. When the long patterned alignment film of the invention
is used to produce, for example, a liquid crystal display device
capable of attaining three-dimensional displays, the respective
widths of the first and second alignment regions are appropriately
decided to correspond to the width of pixel regions formed in a
color filter used in the liquid crystal display device. As
described herein, the respective widths of the first and second
alignment regions are not particularly limited. Usually, the widths
are each preferably from 50 .mu.m to 1000 .mu.m, and more
preferably from 100 .mu.m to 600 .mu.m.
[0069] When the first and second alignment regions are formed in
the pattern in the above-mentioned band form in the invention, a
black line which absorbs light may be laid between the first and
second alignment regions. In this case, the width of the black line
is not particularly limited. Usually, the width is preferably from
10 .mu.m to 30 .mu.m.
[0070] The region where this black line is formed may be a region
having alignment regulating force, or a region having no alignment
regulating force.
[0071] When the first and second alignment regions are formed in
the pattern in the band form in the invention, the respective
directions of the bands in the pattern are not particularly
limited. The directions of the bands may be, for example,
directions parallel to the longitudinal direction (long direction)
of the long patterned alignment film of the invention, directions
orthogonal thereto, or directions crossing the longitudinal
direction obliquely. In the invention, it is preferred in the
invention that the respective directions of the bands in the
pattern are directions parallel to the longitudinal direction of
the long patterned alignment film, in other words, the first and
second alignment regions are formed in a pattern of the form of
bands parallel to the longitudinal direction.
[0072] This matter makes it easy to cause the pattern in which the
first and second retardation regions are formed to have a
relationship corresponding to a pattern in which pixels are formed
in a color filter or some other used in a display device. Moreover,
the matter makes it possible to form a large number of long
patterned retardation films easily by preparing the long alignment
layer into a wound roll form, and unwinding this roll-form long
alignment layer and simultaneously irradiating the alignment layer
with polarized ultraviolet rays while the alignment layer is
continuously fed.
[0073] The respective alignment regulating forces, that is,
directions along which the rodlike compound is caused to be
arranged, which the first and second alignment regions have in the
invention, are not particularly limited as far as the forces or
directions are different from each other. The directions are
different from each other preferably by 90.degree.. This case makes
it possible to form the first and second alignment regions to have
alignment regulating forces for making directions along which the
rodlike compound is caused to be arranged orthogonal to each other,
that is, to make directions of the first and second retardation
regions along each of which the refractive index is the largest
(slow axis directions) orthogonal to each other. Consequently, the
long patterned alignment film of the invention can be rendered a
film usable more suitably for producing a display device capable of
attaining three-dimensional displays.
[0074] Incidentally, the directions different from each other by
90.degree. are not particularly limited as far as the directions
make it possible that when the long patterned alignment film of the
invention is used to form a display device capable of attaining
three-dimensional displays, the three-dimensional displays are
precisely achieved. Usually, the angle between the directions is
preferably within about 90.degree..+-.3.degree., more preferably
within about 90.degree..+-.2.degree., and even more preferably
within about 90.degree..+-.1.degree.. This angle makes it possible
to produce a display device capable of attaining high-performance
three-dimensional displays.
[0075] Specific examples of the first and second regions in which
the directions along which the rodlike compound is caused to be
arranged are different by 90.degree. are preferably directions
having angles of 90.degree. (the first alignment regions 2a) and
0.degree. (the second alignment regions 2b) to the longitudinal
direction of the long patterned alignment film as has already been
illustrated in FIG. 2; and directions having angles of 45.degree.
(the first alignment regions 2a) and 135.degree. (the second
alignment regions 2b) to the longitudinal direction, as illustrated
in FIG. 3. In the case of the directions having the angles of
90.degree. and 0.degree., respectively, the long patterned
alignment film of the invention can be rendered a film usable
suitably for, for example, three-dimensional liquid crystal display
devices in a TN mode. In the case of the directions having the
angles of 45.degree. and 135.degree., respectively, the long
patterned alignment film of the invention can be rendered a film
usable suitably for, for example, three-dimensional liquid crystal
display devices in a VA or IPS mode.
[0076] Reference signs in FIG. 3 represent the same members as in
FIG. 2, respectively. Thus, any description thereabout is omitted
herein. The direction of arrows in each of the alignment regions is
a direction along which the rodlike compound is caused to be
arranged in the region.
[0077] (2) Optical Alignment Material
[0078] The optical alignment material used in the invention is a
material which can exhibit alignment regulating force by
irradiation with polarized ultraviolet rays. The wording "alignment
regulating force" denotes an interaction for arranging the rodlike
compound, which will be detailed later.
[0079] This optical alignment material is not particularly limited
as far as the material is a material which exhibits the alignment
regulating force by irradiation with polarized light. The optical
alignment material can be roughly classified into optical
isomerization material, in which only the molecular form thereof is
changed through cis-trans change to vary the alignment regulating
force reversely, and optical reaction material, in which the
molecule thereof itself is changed by irradiation with polarized
light. In the invention, either one of the optical isomerization
material and the optical reaction material is favorably usable. It
is preferred to use the optical reaction material. As described
above, about the optical reaction material, the molecule reacts by
irradiation with polarized light so that the material exhibits the
alignment regulating force; consequently, the alignment regulating
force can be irreversibly exhibited. Thus, the optical reaction
material shows, over time, a higher stability in the alignment
regulating force.
[0080] The optical reaction material can be further classified in
accordance with the type of the reaction caused by the irradiation
with polarized light. Specifically, the material can be classified
into photo-dimerization type material, in which photo-dimerization
reaction is caused to exhibit the alignment regulating force; photo
decomposition type material, in which photo decomposition reaction
is caused to exhibit the alignment regulating force; photo coupling
type material, in which photo coupling reaction is caused to
exhibit the alignment regulating force; photo
decomposition-coupling type compound, in which photo
decomposition-coupling reaction is caused to exhibit the alignment
regulating force; and others. In the invention, any one of these
optical reaction materials is favorably usable. It is more
preferred from the viewpoint of stability, reactivity (sensitivity)
and others to use, among these materials, photo-dimerization type
material.
[0081] The photo-dimerization type material used in the invention
is not particularly limited as far as the material is a material
which is to undergo photo-dimerization reaction to make it possible
to exhibit alignment regulating force. In the invention, the
wavelength of light for generating the photo-dimerization reaction
is preferably 280 nm or more, in particular preferably from 280 nm
to 400 nm, and more preferably from 300 nm to 380 nm.
[0082] The photo-dimerization type material is, for example, a
polymer having a cinnamate, coumarin, benzylidenephthalimidine,
benzylideneacetophenone, diphenylacetylene, stilbazole, uracil,
quinolinone, maleinimide, or a cinnamylidene acetic acid
derivative. Preferred are a polymer having at least one of a
cinnamate and coumarin, and a polymer having a cinnamate and
coumarin. Specific examples of the photo-dimerization type material
include compounds described in JP-A No. H09-118717, JP-A (Japanese
Translation of PCT Application) No. H10-506420, JP-A (Japanese
Translation of PCT Application) No. 2003-505561, WO 2010/150748, WO
2011/126019, WO 2011/126021, and WO 2011/126022.
[0083] The cinnamate and coumarin in the invention are preferably
compounds each represented by the following formula Ia or Ib:
##STR00001##
[0084] In the formula, A represents pyrimidine-2,5-diyl,
pyridine-2,5-diyl, 2,5-thiophenylene, 2,5-furanylene or 1,4- or
2,6-naphthylene, or represents a phenylene unsubstituted or mono-
or multi-substituted with one or more selected from fluorine atoms,
chlorine atoms, and cyclic, linear or branched alkyl residues each
having 1 to 18 carbon atoms (the residues being each unsubstituted
or mono- or multi-substituted with one or more selected from
fluorine atoms and chlorine atoms, and being each a residue in
which one or more --CH.sub.2-- groups not adjacent to each other
may be each independently substituted with a group C or groups
Cs).
[0085] In the formula, B represents a hydrogen atom, or represents
a group which can react or interact with a second substance, such
as a polymer, oligomer, monomer, optically active polymer,
optically active oligomer and/or optically active monomer, or the
surface.
[0086] In the formula, C represents a group selected from --O--,
--CO--, --CO--O--, --O--CO--, --NR.sub.1--, --NR.sub.1--CO--,
--CO--NR.sub.1--, --NR.sub.1--CO--O--, --O--CO--NR.sub.1--,
--NR.sub.1--CO--NR.sub.1--, --CH.dbd.CH--, --C.ident.C--,
--O--CO--O--, and --Si(CH.sub.3).sub.2--O--Si(CH.sub.3).sub.2-- in
which R.sub.1s each represent a hydrogen atom or a lower alkyl.
[0087] In the formula, D represents a group selected from --O--,
--CO--, --CO--O--, --O--CO--, --NR.sub.1--, --NR.sub.1--CO--,
--CO--NR.sub.1--, --NR.sub.1--CO--O--, --O--CO--NR.sub.1--,
--NR.sub.1--CO--NR.sub.1--, --CH.dbd.CH--, --C.ident.C--,
--O--CO--O--, and --Si(CH.sub.3).sub.2--O--Si(CH.sub.3).sub.2-- in
which R.sub.1s each represent a hydrogen atom or a lower alkyl; an
aromatic group; or an alicyclic group.
[0088] In the formula, S.sub.1 and S.sub.2 each independently
represent a single bond, or a spacer unit, for example, a linear or
branched alkylene group having 1 to 40 carbon atoms (the group
being unsubstituted or mono- or multi-substituted with one or more
selected from fluorine atoms and chlorine atoms, and being a group
in which one or more --CH.sub.2-- groups not adjacent to each other
may be each independently substituted with a group D or groups Ds
provided that oxygen atoms therein are not bonded directly to each
other).
[0089] In the formula, Q represents an oxygen atom or --NR.sub.1--
in which R.sub.1 represents a hydrogen atom or a lower alkyl.
[0090] In the formula, X and Y each independently represent
hydrogen, fluorine, chlorine, cyano, or an alkyl group having 1 to
12 carbon atoms (the group being substituted with fluorine as the
case may be, and being a group in which one or more --CH.sub.2--
groups not adjacent to each other are substituted with --O--,
--CO--O--, --O--CO-- and/or --CH.dbd.CH-- as the case may be.
[0091] As such a photo-dimerization type material, a commercially
available product is usable, a specific example thereof being
ROP-103 (trade name) from Rolic Technologies Ltd., according to WO
08/031,243 and WO 08/130,555.
[0092] The optical alignment material used in the invention may be
a material having refractive index anisotropy. When this optical
alignment material is used, the patterned alignment film produced
by the producing method of the invention is usable as a patterned
retardation film.
[0093] Incidentally, the optical alignment material having
refractive index anisotropy may be specifically any optical
alignment material described in JP-A No. 2002-082224.
[0094] About the optical alignment material used in the invention,
only one species thereof may be used, or two or more species
thereof may be used.
[0095] (3) Alignment Layer
[0096] The alignment layer used in the invention is a layer
containing at least an optical alignment material. The layer may
contain a different compound if necessary.
[0097] The different compound is not particularly limited as far as
the compound does not damage the alignment regulating force of the
alignment layer in the invention. In the invention, the different
compound is preferably a monomer or oligomer having one or more
functional groups. When the alignment layer contains the monomer or
oligomer, the alignment layer can be rendered a layer excellent in
adhesiveness onto a retardation layer formed onto the alignment
layer and containing a rodlike compound having refractive index
anisotropy.
[0098] Examples of the monomer or oligomer used in the invention
include monofunctional monomers each having an acrylate type
functional group (such as reactive ethyl (meth)acrylate, ethylhexyl
(meth)acrylate, styrene, methylstyrene, and N-vinyl pyrrolidone);
polyfunctional monomers (such as polymethylolpropane
tri(meth)acrylate, hexanediol (meth)acrylate,
triethylene(polypropylene) glycol diacrylate, tripropylene glycol
di(meth)acrylate, diethylene glycol di(meth)acrylate,
pentaerythritol tri(meth)acrylate, dipentaerythritol
hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl
glycol di(meth)acrylate, and isocyanuric acid poly(meth)acrylates
(such as isocyanuric acid EO diacrylate)); and bisphenol fluorene
derivatives (such as bisphenoxyethanol fluorene di(meth)acrylate,
and bisphenol fluorene diepoxy (meth)acrylate). These may be used
alone or in the form of a mixture.
[0099] It is preferred to use, as the monomer or oligomer, a
compound in a solid form at room temperature (20 to 25.degree. C.)
This case makes it possible that even when a
long-alignment-film-forming film in which an
alignment-layer-forming layer is laminated on a transparent film
substrate is stored in the state of being wound into a roll form,
the generation of blocking is prevented which results from a matter
that the alignment-layer-forming layer bonds to the rear surface of
the transparent substrate.
[0100] The content of the monomer or oligomer in the invention is
not particularly limited as far as the content does not cause the
alignment regulating force of the alignment layer to be damaged and
causes the alignment layer to exhibit a desired adhesiveness and
others. The content is preferably from 0.01 to 3 times the mass of
the optical alignment material, and in particular preferably from
0.05 to 1.5 times the mass.
[0101] The thickness of the alignment layer in the invention is not
particularly limited as far as the alignment layer can exhibit a
desired alignment regulating force to the rodlike compound having
refractive index anisotropy, the compound being to be detailed
later. Usually, the thickness is preferably from 0.01 .mu.m to 1.0
.mu.m, more preferably from 0.03 .mu.m to 0.5 .mu.m, and in
particular preferably from 0.05 .mu.m to 0.20 .mu.m.
[0102] 2. Long Patterned Alignment Film
[0103] The long patterned alignment film of the invention is a film
comprising at least an alignment layer. Usually, the long patterned
alignment film has a transparent film substrate formed on the
alignment layer. This case makes it possible to form the alignment
layer in a long form easily by preparing the transparent film
substrate into a long form, and then applying, onto this long
transparent film substrate, an alignment-layer-forming coating
solution containing an optical alignment material as described
above.
[0104] In the invention, the long patterned alignment film may have
a different constituent if necessary. An example of the different
constituent is an antiglare layer or antireflective layer 5 as
illustrated in FIG. 4, which is formed on a surface of the
transparent film substrate 1 that is opposite to the surface
thereof on which the alignment layer 2 is formed. This case makes
it possible to form, when a display device is produced, a patterned
retardation film capable of making the produced display device good
in display quality.
[0105] Incidentally, reference signs in FIG. 4 represent the same
members as in FIG. 1, respectively. Thus, description thereabout is
omitted herein.
[0106] (1) Transparent Film Substrate
[0107] The transparent film substrate used in the invention is a
substrate having a function of supporting the alignment layer
and/or others, and formed into a long form.
[0108] The transparent film substrate used in the invention is
preferably a substrate low in retardation. More specifically, about
the transparent film substrate used in the invention, the in-plane
retardation value (Re value) is preferably from 0 nm to 10 nm, more
preferably from 0 nm to 5 nm, and even more preferably from 0 nm to
3 nm. If the in-plane retardation value of the transparent film
substrate is larger than the range, a display device formed by use
of the long patterned alignment film of the invention so as to be
capable of displaying three-dimensional pictures may become bad in
display quality.
[0109] About the transparent film substrate used in the invention,
the transmittance in the visible light band is preferably 80% or
more, and more preferably 90% or more. The transmittance of any
transparent film substrate is measurable according to JIS K7361-1
(Method for Testing Total Light Transmittance of Plastic
Transparent Material).
[0110] The transparent film substrate used in the invention is
preferably a flexible material having such a flexibility that the
substrate can be wound into a roll form.
[0111] Examples of the flexible material include cellulose
derivatives, norbornene based polymers, cycloolefin based polymers,
polymethyl methacrylate, polyvinyl alcohol, polyimide, polyarylate,
polyethylene terephthalate, polysulfone, polyethersulfone,
amorphous polyolefin, denatured acyclic polymer, polystyrene, an
epoxy resin, polycarbonate, and polyester. It is preferred to use,
among these examples, cellulose derivatives. The cellulose
derivatives are particularly good in optical isotropy; thus, in the
case of using the long patterned alignment film of the invention to
form a patterned retardation film, the film can be made excellent
in optical properties.
[0112] It is preferred in the invention to use, among the cellulose
derivatives, cellulose esters. It is more preferred to use, among
the cellulose esters, any cellulose acylate. Since the cellulose
acylate is industrially widely used, the acylate is favorable in
availability.
[0113] The cellulose acylate is preferably a lower aliphatic acid
ester having 2 to 4 carbon atoms. The lower aliphatic acid ester
may be a compound containing only a single lower aliphatic acid
ester, such as cellulose acetate, or may be a compound containing
multiple aliphatic acid esters, such as cellulose acetate butyrate,
or cellulose acetate propionate.
[0114] It is particularly preferred in the invention to use, among
species of the lower aliphatic acid ester, cellulose acetate. The
most preferably usable species of cellulose acetate is a
triactylcellulose having an average acetylation degree of 57.5 to
62.5% (substitution degree: 2.6 to 3.0). The acetylation degree
means the quantity of bonded acetic acid per cellulose-unit-mass.
The acetylation degree can be obtained by measurement and
calculation of the degree of acetylation according to ASTM:
D-817-91 (Method for Testing Cellulose Acetate and Others).
Incidentally, the acetylation degree of a triacetylcellulose
constituting a triacetylcellulose film can be obtained by this
method after a plasticizer and other impurities contained in the
film are removed.
[0115] The thickness of the transparent film substrate used in the
invention is not particularly limited as far as the thickness can
give the long patterned alignment film of the invention
self-supporting property necessary for the film in accordance with
a use purpose of the long patterned alignment film, and others.
Usually, the thickness is preferably from 25 .mu.m to 125 .mu.m,
more preferably from 40 .mu.m to 100 .mu.m, and in particular
preferably 60 .mu.m to 80 .mu.m. If the thickness of the
transparent film substrate is smaller than the range, the
self-supporting property necessary for the long patterned alignment
film of the invention may not be given to the film. If the
thickness is larger than the range, for example, the following may
be caused at the time of cutting the long patterned alignment film
of the invention to be turned into patterned retardation films in a
sheet-like form: wastes from the cutting are increased, or the
cutting blade is rapidly worn away.
[0116] The structure of the transparent film substrate used in the
invention is not limited to a structure made of a single layer.
Thus, the structure may be a structure in which multiple layers are
laminated onto each other. When the transparent film substrate has
the latter structure, in which multiple layers are laminated onto
each other, these laminated layers may be layers identical to each
other in composition, or layers different from each other in
composition.
[0117] The transparent film substrate used in the invention is made
in a long form, and the length and other factors thereof may be
equivalent to those of the above-mentioned alignment layer.
[0118] (2) Antiglare Layer and Antireflective Layer
[0119] When an antireflective layer as described above is formed in
the invention, the advantage is produced that when the long
patterned alignment film of the invention is used to produce a
liquid crystal display device, the produced liquid crystal display
device can give a good display quality. Either one of the antiglare
layer and the antireflective layer may be used, or both thereof may
be used.
[0120] The antiglare layer is a layer having a function of
decreasing a projection of external light from the sun, a
fluorescent lamp or some other onto the display screen of the
display device, this projection being generated by a matter that
the external light is radiated onto the screen and then reflected
thereon. The antireflective layer is a layer having a function of
restraining the regular reflectivity on the front surface to make
the contrast of any image thereon good, thereby improving the
visibility of the image. The antiglare layer or the antireflective
layer used in the invention is not particularly limited as far as
the layer has a desired antiglare function or antireflective
function. The layer may be an antiglare layer or antireflective
layer known generally as such a layer as used in a display device
for improving the display quality thereof. The antiglare layer may
be, for example, a resin layer in which fine particles are
dispersed, and the antireflective layer may be, for example, a
layer having a structure in which layers having different
refractive indexes are laminated onto each other.
[0121] Incidentally, when the antireflective layer is laid onto the
outermost surface of the antiglare layer, the image visibility in a
bright room can be further improved.
[0122] 3. Method for Producing Long Patterned Alignment Film
[0123] The method for producing any long patterned alignment film
of the invention is not particularly limited as far as the method
is a method capable of producing, with stability, the long
patterned alignment film, which comprises at least the alignment
layer detailed above. The method may be an ordinary
alignment-layer-producing method.
[0124] In the invention, the method is preferably a method having:
a preparing step of applying, onto a long transparent film
substrate, an alignment-layer-forming coating solution containing
an optical alignment material to form a long-alignment-film-forming
film having a non-aligned alignment-layer-forming layer; and an
exposing step involving a first exposing processing of feeding the
long-alignment-film-forming film continuously, and simultaneously
irradiating the alignment-layer-forming layer with polarized
ultraviolet rays, and a second exposing processing of irradiating
the resultant with polarized ultraviolet rays different in
polarization direction from those radiated in the first exposing
processing, in which in at least one of the first and second
exposing processing, the polarized ultraviolet rays are patternwise
radiated onto the alignment-layer-forming layer. This method makes
it possible to form a long patterned alignment film easily and
continuously.
[0125] Referring to some of the drawings, a description will be
made about the method for producing a long patterned alignment film
of the invention. FIGS. 5A to 5D are a process chart illustrating
an example of this method, which is for producing a long patterned
alignment film of the invention. As illustrated in FIGS. 5A to 5D,
an alignment-layer-forming coating solution is initially applied
onto a transparent film substrate 1 (FIG. 5A) to form a
long-alignment-film-forming film 3 having the transparent film
substrate 1 and an alignment-layer-forming layer 2' formed on the
transparent film substrate 1 and containing an optical alignment
material. While this long-alignment-film-forming film 3 is
continuously fed, polarized ultraviolet rays are patternwise
radiated through a mask onto the alignment-layer-forming layer 2'
(FIG. 5B) to form first alignment regions 2a. Next, polarized
ultraviolet rays different from the ultraviolet rays used when the
first alignment regions 2a are formed are radiated onto the entire
front surface (FIG. 5C) to form second alignment regions 2b
different from the first alignment regions 2a in a direction along
which the rodlike compound is caused to be arranged. In this way, a
long patterned alignment film 10 is yielded (FIG. 5D).
[0126] In this example, FIG. 5A illustrates the preparing step.
FIGS. 5B to C illustrate the exposing step. FIG. 5B illustrates the
first exposing processing; and FIG. 5C the second exposing
processing.
[0127] Referring to some of the drawings, a description will be
made about a long-patterned-alignment-film producing apparatus used
to form such a long patterned alignment film.
[0128] FIGS. 6 and 7 are each a schematic view illustrating an
example of the long-patterned-alignment-film producing apparatus.
As illustrated in each of FIGS. 6 and 7, a
long-patterned-alignment-film producing apparatus 30 has a feeding
unit containing a winding/unwinding unit 31a and a feeding roll 31b
for feeding the transparent film substrate 1 continuously, and an
exposing unit having a first exposing part 32a and a second
exposing part 32b for radiating polarized ultraviolet rays onto the
alignment-layer-forming layer of the above-mentioned
long-alignment-film-forming film 3, which is being continuously
fed. The apparatus also has, on the transparent film substrate 1,
an applicator 33a for applying an alignment-layer-forming coating
solution to form an alignment-layer-forming layer, and a drying
device 33b for drying the coated film.
[0129] In FIG. 6, the first exposing part 32a includes a light
source 34 for radiating ultraviolet rays orthogonally onto the
alignment-layer-forming layer, a polarizer 35, and a mask 36 having
openings in a pattern form. This part is a part for radiating the
ultraviolet rays patternwise onto the long-alignment-film-forming
film 3 on the feeding roll. The second exposing part 32b has a
polarizer 35 different in polarization axis direction from the
first exposing part.
[0130] In FIG. 7, both of the first exposing part 32a and the
second exposing part 32b have the mask 36 and another mask 36, and
are each a part for radiating polarized ultraviolet rays
patternwise onto the alignment-layer-forming layer on the feeding
roll 31b.
[0131] (1) Preparing Step
[0132] The preparing step in the invention is a step of forming a
long-alignment-film-forming film having a transparent film
substrate, and an alignment-layer-forming layer formed on the
transparent film substrate and containing an optical alignment
material.
[0133] In the step, the method for forming the
alignment-layer-forming layer containing the optical alignment
material is not particularly limited as far as the method is a
method capable of forming the alignment-layer-forming layer
containing the optical alignment material into a desired thickness.
An example thereof is a method of applying, onto the transparent
film substrate, the alignment-layer-forming layer containing the
optical alignment material.
[0134] The content by percentage of the optical alignment material
in the alignment-layer-forming coating solution is not particularly
limited as far as the content is within a range capable of
preparing the alignment-layer-forming coating solution to have a
desired viscosity in accordance with the applying method and
others. In the step, the content by percentage of the optical
alignment material in the alignment-layer-forming coating solution
is preferably from 0.5% by mass to 50% by mass, more preferably
from 1% by mass to 30% by mass, and even more preferably from 2% by
mass to 20% by mass. If the content by percentage of the optical
alignment material is larger than the range, it may be difficult
dependently on the applying method to form an
alignment-layer-forming layer excellent in planarity. Moreover, if
the content by percentage is smaller than the range, a load for
drying the solvent increases so that the applying velocity may not
be adjusted into a desired range.
[0135] The solvent used in the alignment-layer-forming coating
solution in the step is not particularly limited as far as the
solvent is a solvent in which the optical alignment material and
others can each be dissolved into a desired concentration. Examples
thereof include hydrocarbon solvents such as benzene and hexane;
ketone solvents such as methyl ethyl ketone, methyl isobutyl
ketone, and cyclohexanone; ether solvents such as tetrahydrofuran,
1,2-dimethoxyethane, and propylene glycol monoethyl ether (PGME);
halogenated alkyl solvents such as chloroform, and dichloromethane;
ester solvents such as methyl acetate, ethyl acetate, butyl
acetate, and propylene glycol monomethyl ether acetate; amide
solvents such as N,N-dimethylformamide; sulfoxide solvents such as
dimethylsulfoxide; anone solvents as cyclohexanone; and alcohol
solvents such as methanol, ethanol, and propanol. However, the
solvent is not limited thereto. About the solvent used in the step,
a single species thereof may be used, or two or more species
thereof may be used in a mixture form.
[0136] The method for applying the alignment-layer-forming coating
solution in the step is not particularly limited as far as the
method is a method enabling the resultant to attain a desired
planarity. Specific examples of the applying method include gravure
coating, reverse coating, knife coating, dip coating, spray
coating, air knife coating, spin coating, roll coating, printing,
dip pulling, curtain coating, die coating, casting, bar coating,
extrusion coating, and E-type painting methods.
[0137] The thickness of a coated film resulting from the
alignment-layer-forming coating solution is not particularly
limited as far as the thickness is within a range enabling the
coated film to attain a desired planarity. Usually, the thickness
is preferably from 0.1 to 50 .mu.m, in particular preferably from
0.5 .mu.m to 30 .mu.m, and more preferably from 0.5 .mu.m to 10
.mu.m.
[0138] The method for drying the coated film resulting from the
alignment-layer-forming coating solution may be an ordinarily
usable drying method, such as a heat drying method, a
reduced-pressure drying method, or a gap drying method. The drying
method in the step is not limited to any single method. Thus, for
the method, multiple manners may be adopted, for example, an
embodiment may be adopted in which the drying method is
successively changed in accordance with the remaining amount of the
solvent.
[0139] Furthermore, the method for drying the coated film resulting
from the alignment-layer-forming coating solution may be a method
of blowing drying wind adjusted to a constant temperature onto the
coated film. When such a drying method is used, the velocity of the
dry wind-blown onto the coated film is preferably 3 m/second or
less, and in particular preferably 0.5 m/second or less.
[0140] The long-alignment-film-forming film formed in the step
contains at least the transparent film substrate and the
alignment-layer-forming layer. If necessary, the film may have an
intermediate layer (for example, a layer obtained by curing a
crosslinkable monomer such as pentaerythritol triacrylate (PETA)
and having a thickness of about 1 .mu.m) in order to improve the
adhesiveness between the transparent film substrate and the
alignment-layer-forming layer, and improve the film in barrier
performance for preventing the shift of components, such as a
plasticizer, from the transparent film substrate to the
alignment-layer-forming layer, or the shift of the optical
alignment material contained in the alignment-layer-forming layer
to the transparent film substrate.
[0141] (2) Exposing Step
[0142] The exposing step in the invention is a step involving a
first exposing processing of feeding the
long-alignment-film-forming film continuously, and simultaneously
irradiating the alignment-layer-forming layer with polarized
ultraviolet rays, and a second exposing processing of irradiating
the resultant with polarized ultraviolet rays different in
polarization direction from those radiated in the first exposing
processing, in which in at least one of the first and second
exposing processing, the polarized ultraviolet rays are patternwise
radiated onto the alignment-layer-forming layer.
[0143] In the step, the method for feeding the
long-alignment-film-forming film is not particularly limited as far
as the method is a method capable of feeding the
long-alignment-film-forming film continuously. Thus, the method may
be a method using an ordinary feeding unit. Specific examples
thereof include a method using an unwinding unit for supplying the
long-alignment-film-forming film in a roll form, a winding unit for
winding the long-alignment-film-forming film and a long patterned
alignment film, or the like; and a method using a belt conveyer, a
feeding roll, or the like. The method may be a method using a
floating-type feeding bed for feeding the
long-alignment-film-forming film in a floating state by discharge
and suction of air.
[0144] As far as the method is a method capable of feeding the
long-alignment-film-forming film continuously and stably, it is not
particularly limited whether or not a tension is applied to the
long-alignment-film-forming film when the film is fed. Preferably,
the film is fed preferably in the state that a predetermined
tension is applied thereto. This case makes it possible to feed the
film continuously and more stably.
[0145] When the feeding unit used in the step is arranged at a
position where polarized ultraviolet rays are radiated onto the
long-alignment-film-forming film, the color of the feeding unit is
preferably a color on which the polarized ultraviolet rays
transmitted through the long-alignment-film-forming film are not
reflected. Specifically, the color is preferably black. The method
for making the feeding unit black is, for example, a method of
subjecting the surface thereof to chromium treatment.
[0146] The shape of the feeding roll in the step is not
particularly limited as far as the shape is a shape enabling the
long-alignment-film-forming film to be stably fed. When the feeding
roll is arranged at a position where polarized ultraviolet rays are
radiated onto the long-alignment-film-forming film, it is preferred
that the shape makes it possible to keep a constant distance
between the front surface of the alignment-layer-forming layer of
the long-alignment-film-forming film and the exposing unit.
Usually, the shape is a completely round shape.
[0147] The respective polarization directions of polarized
ultraviolet rays radiated in the first exposing processing and the
second exposing processing in the step may be polarization
directions along which the rodlike compound in the first alignment
region and that in the second alignment region are caused to be
arranged, respectively.
[0148] Specifically, when the optical alignment material exhibits
alignment regulating force for arranging the rodlike compound in a
direction along the polarization direction of the polarized
ultraviolet rays, the respective directions of the polarized rays
radiated in the first and second exposing processings can be each
made identical with a direction along which the rodlike compound is
caused to be arranged.
[0149] The polarized ultraviolet rays radiated in the step may or
may not undergo light collection. When the above-mentioned
pattern-radiation is applied to the long-alignment-film-forming
film on the feeding roll as will be detailed later, that is, when a
difference is generated in the distance between the light source of
the polarized ultraviolet ray and the ultraviolet-ray-radiated-spot
inside a region where the polarized ultraviolet rays are to be
radiated, it is preferred that the polarized ultraviolet rays
undergo light collection in the feeding direction. This case makes
it possible to decrease an effect based on the distance from the
light source to form the alignment regions with a good
pattern-precision.
[0150] Incidentally, the method for such a light collection may be
an ordinarily usable method, for example, a method using a light
collecting reflector or light collecting lens having a desired
shape. In the invention, the method is preferably a method of
making the polarized ultraviolet rays parallel to a direction
(width direction) orthogonal to the feeding direction. The method
for the parallelization may be an ordinarily usable method, for
example, a method using a light collecting reflector or light
collecting lens having a desired shape.
[0151] The wavelength of the polarized ultraviolet rays radiated in
the step is appropriately set in accordance with the optical
alignment material, and others, and may be a wavelength usable when
an ordinary optical alignment material is caused to exhibit
alignment regulating force. Specifically, the wavelength of the
used radiated light is preferably from 210 nm to 380 nm, more
preferably 230 nm to 380 nm, and even more preferably from 250 nm
to 380 nm.
[0152] Examples of a light source of such ultraviolet rays include
low-pressure mercury lamps (a sterilizing lamp, a fluorescent
chemical lamp, and a black light), high-pressure discharge lamps (a
high-pressure mercury lamp, and a metal halide lamp), and short arc
discharge lamps (a super high-pressure mercury lamp, a xenon lamp,
and a mercury xenon lamp). It is preferred to use, among these
light sources, a metal halide lamp, a xenon lamp, a high-pressure
mercury lamp, or some other.
[0153] The method for generating the polarized ultraviolet rays
radiated in the step is not particularly limited as far as the
method is a method capable of radiating the polarized ultraviolet
rays stably. The method may be a method of radiating ultraviolet
rays through a polarizer that can transmit only polarized light
rays having some direction.
[0154] The polarizer may be a polarizer usable ordinarily for the
generation of polarized light. Examples thereof include a wire grid
type polarizer having slit-form openings, and a polarizer making
use of a polarized-light-separating method using a Brewster's angle
made by laminating multiple quartz plates onto each other, or a
polarized-light-separating method using a Brewster's angle of a
film made of vapor-deposited layers different from each other in
refractive index.
[0155] The irradiance of the polarized ultraviolet rays radiated in
the step is not particularly limited as far as the irradiance is an
irradiance making it possible to form each of the alignment regions
that has a desired alignment regulating force. When the wavelength
is, for example, 310 nm, the irradiance is preferably from 5
mJ/cm.sup.2 to 500 mJ/cm.sup.2, more preferably from 7 mJ/cm.sup.2
to 300 mJ/cm.sup.2, and even more preferably from 10 mJ/cm.sup.2 to
100 mJ/cm.sup.2. The irradiance makes it possible to form each of
the alignment regions that has a sufficient alignment regulating
force.
[0156] The irradiation distance of the polarized ultraviolet rays
in the step, that is, the distance in the feeding direction of a
long-alignment-film-forming film that receives the radiation of the
polarized ultraviolet rays is not particularly limited as far as
the distance permits the above-mentioned irradiance to be attained
in each of the exposing processing. The irradiation distance may be
appropriately set in accordance with the line velocity and
others.
[0157] When the irradiation distance is short in the step, the
advantage is produced that the pattern precision can easily be made
high. When the irradiation distance is long, the advantage is
produced that even when the line velocity is large, an alignment
region having a sufficient alignment regulating force can be
formed.
[0158] The method for making the irradiation distance long may be a
method of pluralizing the number of times of the radiation of the
polarized ultraviolet rays in each of the exposing processing, or
widening the irradiation area into the feeding direction.
[0159] The method for radiating the polarized ultraviolet rays in
the first and second exposing processings is not particularly
limited as far as the method is a method in which the polarized
ultraviolet rays are patternwise radiated onto the
alignment-layer-forming layer in at least one of these processing,
and is further a method capable of forming first and second
alignment regions which show different directions along each of
which the rodlike compound is caused to be arranged. Specifically,
the method may be a method in which the first exposing processing
is full-surface-radiation and the second exposing processing is
pattern-radiation (a first embodiment), in which the first exposing
processing is pattern-radiation and the second exposing processing
is full-surface-radiation (a second embodiment), or in which the
first exposing processing is pattern-radiation and the second
exposing processing is pattern-radiation (a third embodiment). In
the case of the first embodiment, the first and second alignment
regions can be formed by using, as the alignment-layer-forming
layer, a layer containing a material capable of changing alignment
regulating force reversibly, such as a photo isomerization
material. Specifically, as illustrated in FIGS. 8A to 8C,
full-surface-radiation is performed as the first exposing
processing (FIG. 8A), and next pattern-radiation is performed,
using polarized ultraviolet rays different in polarization
direction from those used in the first exposing processing (FIG.
8B). In this way, first and second alignment regions can be formed
(FIG. 8C).
[0160] In the case of the second embodiment, the first and second
alignment regions can be formed by using, as the
alignment-layer-forming layer, a layer containing a material
incapable of changing alignment regulating force reversibly, such
as a photoreactive material (such as a photo-dimerization
material). Specifically, as has been illustrated in FIGS. 5A to 5D,
pattern-radiation is performed as the first exposing processing
(FIG. 5B), and next full-surface-radiation is performed as the
second exposing processing, using polarized ultraviolet rays
different in polarization direction from those used in the first
exposing processing (FIG. 5C). In this way, first and second
alignment regions can be formed (FIG. 5D).
[0161] In the case of the third embodiment, the first and second
alignment regions can be formed by using, as the
alignment-layer-forming layer, a layer containing a material
capable or incapable of changing alignment regulating force
reversibly. Specifically, as illustrated in FIGS. 9A to 9C,
pattern-radiation is performed as the first exposing processing
(FIG. 9A), and next pattern-radiation is performed in a region
different from the region irradiated in the first exposing
processing, using polarized ultraviolet rays different in
polarization direction from those used in the first exposing
processing (FIG. 9B). In this way, first and second alignment
regions can be formed (FIG. 9C).
[0162] Reference signs in FIGS. 8 to 9 represent the same members
as in FIG. 1, respectively. Thus, description thereabout is omitted
herein.
[0163] In the present step, it is preferred that one of the first
and second exposing processing is pattern-radiation while the other
is full-surface-radiation. The second embodiment is particularly
preferred, in which the first exposing processing is
pattern-radiation while the second exposing processing is
full-surface-radiation. In a case where the other is
full-surface-radiation, facilities for performing the exposing step
can be made simple to form, easily at low costs, the first and
second alignment regions, where the rodlike compound can be
arranged in directions different from each other.
[0164] Furthermore, since the first and second exposing processes
do not require pattern matching, this case makes it possible to
form easily the first and second alignment regions good in pattern
precision.
[0165] Additionally, the method of the second embodiment makes it
possible to use, as the material constituting the
alignment-layer-forming layer, a photoreactive material as
described above, which is excellent in
alignment-regulating-force-stability over time.
[0166] The method for performing (each of) the pattern-radiation(s)
in the step is not particularly limited as far as the method is a
method capable of radiating polarized ultraviolet rays with a good
pattern precision. It is preferred that the pattern-radiation is
performed on the feeding unit for feeding the
long-alignment-film-forming film, that is, that the exposing part
and the feeding unit for performing the pattern-radiation are
arranged to apply the pattern-radiation onto the
long-alignment-film-forming film on the feeding unit. It is
particularly preferred that the feeding unit for feeding a region
of the long-alignment-film-forming film that receives the
pattern-radiation is a feeding roll, that is, that the
pattern-radiation is applied onto the long-alignment-film-forming
film on a feeding roll. This case makes it possible to keep a
constant distance stable between the light source and the
long-alignment-film-forming film to form, with a good precision,
the first and second alignment regions, where the rodlike compound
can be arranged into directions different from each other. The case
also makes it possible to keep a constant distance stable easily
between the light source and the long-alignment-film-forming film
by use of the feeding roll.
[0167] In the case of performing the pattern-radiation in the step
to make the irradiation distance long, specifically, in the case of
pluralizing the number of times of radiation of polarized
ultraviolet rays in each of the exposing processing or widening the
irradiation area into the feeding direction to attain the
pattern-radiation, the method for the pattern-radiation is not
particularly limited as far as the method is a method capable of
forming, with a good pattern precision, the patterned alignment
region formed in each of the exposing processing. Preferably, the
method is a method of performing the individual
ray-patternwise-radiating operations in each of the exposing
processing on the same feeding unit. In other words, it is
preferred to arrange one or more exposing units and one or more
feeding units for performing each of the exposing processing in
such a manner that the ray-patternwise-radiating operations are
applied to the long-alignment-film-forming film on the same feeding
unit. When the ray-patternwise-radiating operations are made on the
same feeding unit, the long-alignment-film-forming film that is
being fed can be prevented from being vibrated or shifted in the
width direction. Thus, polarized ultraviolet rays can be radiated
thereto with a good pattern precision.
[0168] Specifically, when the number of times of the
ray-patternwise-radiation in each of the pattern-radiations is
plural, it is preferred that the multiple ray-radiating operations
performed in the pattern-radiation are attained on the same feeding
unit, that is, that the pattern-radiations are each multiple
ray-patternwise-radiating operations, and further one or more
exposing units and one or more feeding units are arranged in such a
manner that the ray-patternwise-radiating operations, in each of
the exposing processing, are attained on the same feeding unit.
When the ray-patternwise-radiating operations, in each of the
exposing processing, are attained on the same feeding unit, in each
of pattern-radiating-operation-intervals included in the
ray-patternwise-radiating operations the pattern position is easily
matched with the position of the long-alignment-film-forming film.
Thus, the first and second alignment regions can be formed with a
good pattern precision. Even when the irradiance is short according
to one ray-patternwise-radiating operation, a sufficient irradiance
can be attained by the multiple ray-radiating operations onto the
same spot. Thus, the long-alignment-film-forming film can be fed at
a high velocity.
[0169] FIG. 10 is an explanatory view illustrating an example in
which when the first exposing processing is a processing of
performing multiple operations of ray-patternwise-radiation from
multiple first exposing parts 32a, the ray-patternwise-radiating
operations are attained on the same feeding unit.
[0170] When both of the first and second exposing processings are
pattern-radiations (the third embodiment), the method for
performing the pattern-radiations may be a method of making
respective patterning-operations in both of the processings on
different feeding units. It is however preferred to perform the
respective pattern-radiations of both the processings on the same
feeding unit, that is, to arrange one or more exposing units and
one or more feeding units to apply the first and second exposing
parts for performing the first and second exposing processings onto
the long-alignment-film-forming film on the same feeding unit. When
the pattern-radiations are performed on the same feeding unit, the
positions of patterns thereof are easily matched with the
long-alignment-film-forming film between the first and second
exposing processings. Thus, the first and second alignment regions
can be formed with a good pattern precision.
[0171] FIG. 11 is an explanatory view illustrating an example in
which the first and second exposing processings are
pattern-radiations such that polarized ultraviolet rays are
patternwise radiated from first and second exposing parts 32a and
32b, respectively, and further the respective pattern-radiations in
both the processings are attained on the same feeding unit.
[0172] When both of the first and second exposing processings are,
in the present step, pattern-radiations as in the third embodiment,
patterns of the pattern-radiations of the first and second exposing
processings may have a region not irradiated with any polarized
ultraviolet ray (non-irradiated region) between the first and
second alignment regions.
[0173] FIGS. 12A to 12D are a process chart illustrating an example
of the case of forming non-irradiated regions. As illustrated in
FIGS. 12A to 12D, in both of first and second exposing processings,
a mask is used which has light-shielding portions where the
radiation of polarized ultraviolet rays is blocked (FIGS. 12A to
12B) to make it possible to form non-irradiated regions 2c
(non-alignment regions 2c) between first and second alignment
regions when these are viewed in plane, as illustrated in FIG.
12C.
[0174] Incidentally, in the non-irradiated regions 2c, its optical
alignment material is not irradiated with the polarized ultraviolet
rays, so that these regions are non-alignment regions where
alignment regulating force has not been exhibited. The rodlike
compound, having refractive index anisotropy, formed on the
non-alignment regions can be made into buffer regions that are in a
state that the rodlike compound has not been aligned (the alignment
directions of individual molecules of the rodlike compound are
distributed to be at random). Specifically, as illustrated in FIG.
12D, the following is attained in the case of forming an
retardation layer onto an alignment layer 2 made of a pattern that
first alignment regions 2a, non-alignment regions 2c and second
alignment regions 2b are, in this order, arranged or repeated one
or more times when viewed in plane, so as to contain the
non-alignment regions: the retardation layer 4 is made of a pattern
such that first retardation regions 4a positioned just on the first
alignment regions 2a, buffer regions 4c positioned just on the
non-irradiated regions 2c (the regions may be referred to as
non-alignment regions 2c when understood as a
production-process-resulting product), and the second retardation
regions 4b just on the second alignment regions 2b are, in this
order, arranged or repeated one or more times when viewed in plane.
The structure of the retardation layer when viewed in plane is a
structure, in which any one of the buffer regions 4c, in the form
of a narrow-width band, is sandwiched between one of the first
retardation regions 4a and the (adjacent) second retardation
regions 4b. The width of the non-alignment regions (non-irradiated
regions) 2c or the buffer regions 4c may be adjusted into the range
of about 0.1 .mu.m to 10 .mu.m. In a resultant long patterned
retardation film 20, the following is caused when the pattern of
the retardation layer 4 when viewed in plane is a pattern such that
first retardation regions 4a, a buffer regions 4c and a second
retardation regions 4b are, in this order, arranged or repeated one
or more times: the vicinity of boundary lines between the first and
second retardation regions 4a and 4b becomes obscure images of
transmitted light to reduce moire (striped pattern) based on
interference between the cycle period of the pixels and that of the
first and second retardation regions 4a and 4b. Consequently,
produced is an advantageous effect that no moire are generated, or
that even when moire are generated, the level thereof is
reduced.
[0175] Reference signs in FIGS. 12A to 12D represent the same
members as in FIG. 1, respectively. Thus, description thereabout is
omitted herein.
[0176] The method for forming each of the patterns in the present
step is not particularly limited as far as the method is a method
of radiating polarized ultraviolet rays into a desired pattern. The
method is usually a method of arranging, between the
long-alignment-film-forming film and the light source, a mask
having openings through which polarized ultraviolet rays are
transmitted only into a desired pattern form.
[0177] The material constituting the mask in the step is not
particularly limited as far as the material is a material capable
of forming desired openings in a product of the material. The
material may be any metal that is hardly deteriorated by
ultraviolet rays, or quartz. In the step, the mask is preferably a
mask in which Cr is patternwise vapor-deposited on synthetic
quartz. This mask is excellent in dimensional stability against a
change in temperature or humidity, and others so that the alignment
regions can be formed in the alignment-layer-forming layer with a
good pattern precision.
[0178] The method for performing the full-surface-radiation in the
present step is not particularly limited as far as the method is
method capable of radiating polarized ultraviolet rays stably into
a predetermined scope. It is preferred to apply the
full-surface-radiation to the long-alignment-film-forming film
between members of the feeding unit. It is particularly preferred
to apply the full-surface-radiation to the
long-alignment-film-forming film positioned between feeding rolls.
This case makes it possible to attain low costs. The case also
makes it possible to make the timing of performing the exposing
step highly flexible.
[0179] When polarized ultraviolet rays are radiated onto the
alignment-layer-forming layer in the step, it is preferred to make
temperature-adjustment to make the temperature of the
alignment-layer-forming layer constant. This case makes it possible
to form the alignment regions with a good precision.
[0180] In the step, the temperature of the alignment-layer-forming
layer is adjusted more preferably in the range of 15.degree. C. to
90.degree. C., and even more preferably 15.degree. C. to 60.degree.
C.
[0181] The method for the temperature-adjustment may be a method
using a temperature-adjusting instrument such as an ordinary
heating/cooling instrument. The method is specifically a method
using an air blower for sending air having a certain temperature,
or a method using, as the feeding unit, a temperature-adjustable
feeding unit, and is more specifically a method using a
temperature-adjustable feeding roll or belt conveyer.
[0182] 6. Usage
[0183] The long patterned alignment film of the invention may be
used for, for example, a patterned retardation film usable in a
three-dimensional display device. The long patterned alignment film
can be in particular preferably used to form patterned retardation
films required to be easily mass-produced.
[0184] B. Long Patterned Retardation Film
[0185] The following will describe the long patterned retardation
film of the invention.
[0186] The long patterned retardation film of the invention
comprises: the long patterned alignment film detailed above, and a
retardation layer formed on the alignment layer of the long
patterned alignment film, and containing a rodlike compound which
has a refractive index anisotropy.
[0187] Referring to some of the drawings, the long patterned
retardation film of the invention is described. FIG. 13 is a
sectional view taken on line B-B in FIG. 15, FIG. 14 is a
perspective view taken on line B-B in FIG. 15, and FIG. 15 is a
schematic plan view illustrating an example of the long patterned
retardation film of the invention. As illustrated in FIGS. 13 to
15, a long patterned retardation film 20 of the invention comprises
a long patterned alignment film 10 as described above, and a
retardation layer 4 formed on an alignment layer 2 included in the
long patterned alignment film 10 and containing a rodlike compound
having refractive index anisotropy. The retardation layer 4 has
first retardation regions 4a and second retardation regions 4b
having the same patterns as first alignment regions 2a and second
alignment regions 2b as describe above, respectively. The rodlike
compound is arranged along respective alignment regulating forces
which these alignment regions have.
[0188] Incidentally, in FIG. 15, the illustration of the
retardation layer is omitted for making the description easy. In
this example, the alignment regulating force which the first
alignment regions have is force for arranging the rodlike compound
in a direction orthogonal to the longitudinal direction while the
force which the second alignment regions have is force for
arranging the rodlike compound in a direction parallel to the
longitudinal direction.
[0189] According to the invention, the long patterned retardation
film has the above-mentioned long patterned alignment film, and
this matter makes it possible to render this long patterned
retardation film a film having a first retardation region and a
second retardation region in which the respective arranging
directions of the rodlike compound are different from each
other.
[0190] It is therefore possible to form easily a large number of
patterned retardation films applicable to three-dimensional display
devices.
[0191] Moreover, the long patterned retardation film is long, and
thus the production process of the patterned retardation can be
made high in flexibility.
[0192] The long patterned retardation film of the invention
comprises at least the long patterned alignment film detailed
above, and a retardation layer.
[0193] Hereinafter, each of the constituents of the long patterned
retardation film of the invention will be described in detail.
[0194] Incidentally, the long patterned alignment film is the same
as described in the item "A. Long Patterned Alignment Film". Thus,
any description thereabout is omitted herein.
[0195] 1. Retardation Layer
[0196] The retardation layer in the invention is a layer formed on
the above-mentioned alignment layer, and contains a rodlike
compound having refractive index anisotropy, thus giving a
retardation property to the long patterned retardation film of the
invention. In the invention, the above-mentioned patterned
alignment film, that is, the alignment layer having the
above-mentioned characteristics is formed; thus, in the retardation
layer in the invention, its first and second retardation regions
are formed in the same pattern as formed in the above-mentioned
first and second alignment regions, respectively, and further the
rodlike compound is arranged in directions along respective
alignment regulating forces which the individual alignment regions
have.
[0197] The retardation layer used in the invention contains the
rodlike compound, which will be detailed later, thus exhibiting a
retardation property. As a result, the degree of the retardation
property is decided dependently on the kind of the rodlike compound
and the thickness of the retardation layer. Consequently, the
thickness of the retardation layer used in the invention is not
particularly limited as the thickness is within a range enabling
the retardation layer to attain a predetermined retardation
property. The thickness is appropriately decided in accordance with
a use purpose of the long patterned retardation film of the
invention, and others. In the retardation layer in the invention,
the first and second retardation regions are substantially equal to
each other in thickness. The thickness of the retardation layer in
the invention is preferably within such a range that the in-plane
retardation of the retardation layer corresponds to .lamda./4. This
matter makes it possible in the long patterned retardation film of
the invention that linearly polarized rays transmitted through the
first and second retardation regions are converted to circularly
polarized rays orthogonal to each other. Thus, the long patterned
retardation film of the invention is usable more suitably for a 3D
display device.
[0198] When the thickness of the retardation layer in the invention
is adjusted to a distance within such a range that the in-plane
retardation of the retardation layer corresponds to .lamda./4, it
is appropriately decided in accordance with the kind of the rodlike
compound, which will be detailed later, what the distance is
specifically set to. In the invention, the distance is usually from
0.5 .mu.m to 2 .mu.m when the rodlike compound is an ordinarily
usable rodlike compound. However, the distance is not limited into
this range.
[0199] The following will describe the rodlike compound contained
in the retardation layer. The rodlike compound used in the
invention has refractive index anisotropy. The rodlike compound
contained in the retardation layer in the invention is not
particularly limited as far as the compound is a compound capable
of being regularly molecular-arranged to give a desired retardation
property to the retardation layer in the invention. The rodlike
compound used in the invention is preferably a liquid crystal
material, which exhibits a liquid crystal property. Since the
liquid crystal material is large in refractive index anisotropy,
the material makes it easy to give a desired retardation property
onto the long patterned retardation film of the invention.
[0200] The liquid crystal material used in the invention may be,
for example, a material exhibiting a liquid crystal phase such as a
nematic phase or a smectic phase. In the invention, a material
exhibiting any one of these liquid crystal phases is preferably
usable. It is particularly preferred to use a liquid crystal
material exhibiting a nematic phase. This nematic-phase-exhibiting
liquid crystal material is more easily caused to be regularly
arranged than liquid crystal materials having any other liquid
crystal phase.
[0201] In the invention, the nematic-phase-exhibiting liquid
crystal material is preferably a material having respective spacers
at both of its mesogen terminals. The material having the spacers
at both of the mesogen terminals is excellent in flexibility; thus,
by use of this liquid crystal material, the long patterned
retardation film of the invention can be made excellent in
transparency.
[0202] The rodlike compound used in the invention is preferably a
compound having in the molecule thereof a polymerizable functional
group, and more preferably a compound having therein a
polymerizable functional group that can be three-dimensionally
crosslinked. When the rodlike compound has a polymerizable
functional group, the rodlike compound can be polymerized to be
fixed. This can result in yielding a retardation layer excellent in
arrangement stability not to be easily changed in retardation
property with time. In the case of using the rodlike compound
having a polymerizable functional group, the retardation layer in
the invention comes to contain the rodlike compound crosslinked
through the polymerizable functional group.
[0203] Incidentally, the wording "three-dimensionally crosslinked"
denotes that the liquid crystal molecules are three-dimensionally
polymerized to be turned to the state of having a net (network)
structure.
[0204] The polymerizable functional group may be, for example, a
polymerizable functional group polymerizable by effect of
ultraviolet rays, ionizing radiations such as an electron beam, or
heat. A typical example of the polymerizable functional group is a
radical polymerizable functional group, or a cation polymerizable
functional group. A typical example of the radical polymerizable
functional group is a functional group having at least one
addition-polymerizable ethylenically unsaturated double bond.
Specific examples thereof include a vinyl group, and an acrylic
group (this wording being used as a generic name of any one of
acryloyl, methacryloyl, acryloyloxy and methacryloyloxy groups)
which each may be substituted or unsubstituted. A specific example
of the cation polymerizable functional group is an epoxy group.
Other examples of the polymerizable functional group include an
isocyanate group, and an unsaturated triple bond. It is preferred
from the viewpoint of the process to use, among these groups, a
functional group having an ethylenically unsaturated double
bond.
[0205] The rodlike compound in the invention is in particular
preferably a liquid crystal material, which exhibits a liquid
crystal property, having at terminals of each molecules
polymerizable functional groups as described above. The use of this
liquid crystal material makes it possible that molecules thereof
are three-dimensionally polymerized with each other to generate a
net (network) structure state to form the above retardation layer
that has alignment stability and is excellent in performance of
exhibiting optical characteristics.
[0206] Incidentally, even when a liquid crystal material having at
a single terminal of each molecule a polymerizable functional group
is used, the material is crosslinked with another molecule so that
the material can be stabilized in alignment.
[0207] Specific examples of the rodlike compound used in the
invention include compounds represented by the formulae (1) to
(17), respectively:
##STR00002## ##STR00003##
[0208] Incidentally, about the rodlike compound, only a single
species thereof may be used, or two or more species thereof may be
used in a mixture form. It is preferred to use a mixture of a
liquid crystal material having at each of both the terminals
thereof one or more polymerizable functional groups and a liquid
crystal material having at a single terminal thereof one or more
polymerizable functional groups since the polymerization density
(crosslinkage density) and optical characteristics thereof are
arbitrarily adjustable by adjusting the blend ratio between the
two. It is preferred from the viewpoint of keeping the reliability
to use a liquid crystal material having at each of both the
terminals thereof one or more polymerizable functional groups. From
the viewpoint of the alignment of the liquid crystal, it is
preferred that each of the terminals has only one polymerizable
functional group.
[0209] 2. Long Patterned Retardation Film
[0210] (1) Other Constituents
[0211] Although the long patterned retardation film of the
invention comprises at least the patterned alignment film and the
retardation layer detailed above, the long patterned retardation
film may comprise a different constituent if necessary. As
illustrated in FIG. 16, examples of the different constituent
include an adhesive layer 6 and a separator 7 each formed on a
retardation layer 4.
[0212] Incidentally, the adhesive layer and the separator in the
invention may be ones usable in ordinary retardation films.
[0213] (2) Long Patterned Retardation Film
[0214] The retardation film of the invention is a film having a
structure in which a first retardation region and a second
retardation region are patternwise formed in a retardation layer to
correspond to a pattern in which first and second alignment regions
as detailed above are formed. The degree of a retardation property
which the first and second retardation regions have is not
particularly limited, and may be appropriately decided in
accordance with a use purpose of the long patterned retardation
film of the invention, and others. Thus, specific numerical value
ranges of the respective in-plane retardations which the first and
second retardation regions exhibit are not particularly limited,
either, and may be appropriately decided in accordance with the use
purpose of the long patterned retardation film. When the long
patterned retardation film of the invention is used to produce a 3D
liquid crystal display device, the in-plane retardation value of
the retardation layer corresponds preferably to .lamda./4. More
specifically, the in-plane retardation value of the retardation
layer is preferably from 100 nm to 160 nm, more preferably from 110
nm to 150 nm, and even more preferably from 120 nm to 140 nm. In
the retardation layer in the invention, the respective in-plane
retardation values which the first and second retardation regions
exhibit are substantially equal to each other although their slow
axis directions are different from each other.
[0215] Here, the in-plane retardation value is an index
representing the degree of the double refractivity of a refractive
index anisotropic body in the in-plane direction thereof. When the
refractive index thereof in the slow axis direction, which is a
direction along which the largest refractive index is exhibited
among the in-plane directions, is represented by Nx, the refractive
index thereof in the fast axis direction orthogonal to the slow
axis direction by Ny, and the thickness of the refractive index
anisotropic body in a direction perpendicular to the in-plane
directions by "d", the in-plane retardation value is a value
represented by the following:
Re [nm]=(Nx-Ny).times.d [nm].
The in-plane retardation value (Re value) is measurable, using, for
example, an instrument, KOBRA-WR.TM., manufactured by Oji
Scientific Instruments by a parallel Nicol rotating method. The
in-plane retardation value of a microscopic area is also
measureable by means of an instrument, AxoScan.TM., manufactured by
Axometrics, Inc. (USA) using a Mueller matrix. In the present
specification, any Re value denotes a value at a wavelength of 589
nm unless otherwise specified.
[0216] In the retardation layer in the invention, the pattern in
which the first and second retardation regions are formed is not
particularly limited, either, and may be appropriately decided in
accordance with a use purpose of the long patterned retardation
film of the invention, and others. Incidentally, the pattern in
which the first and second retardation regions are formed is
consistent with the pattern in which the first and second alignment
regions are formed in the alignment layer. Thus, by selecting the
pattern in which the first and second alignment regions are formed,
the pattern in which the first retardation region and second
retardation region are formed are simultaneously decided.
[0217] The matter that the pattern made of the first and second
retardation regions is formed in the long patterned retardation
film of the invention can be estimated, for example, by putting a
sample into polarizing plates in a crossed Nicol state, and then
verifying that bright lines and dark lines are made reverse to each
other when the sample is rotated. In a case where the pattern made
of the first and second retardation regions is fine at this time,
it is advisable to observe the sample through a polarization
microscope. The direction (angle) of the slow axis inside each of
the patterned regions may be measured with AxoScan.TM. described
above.
[0218] 3. Method for Producing Long Patterned Retardation Film
[0219] The method for producing the long patterned retardation film
of the invention is not particularly limited as far as the method
is a method capable of forming stably a long patterned retardation
film in which the transparent film substrate, alignment layer and
retardation layer detailed above are laminated onto each other in
this order. The method may be a method for producing an ordinary
retardation film.
[0220] A specific example thereof is a method of applying a
retardation-layer-forming coating solution containing a rodlike
compound onto an alignment layer of a patterned alignment film as
detailed above to arrange the rodlike compound contained in the
resultant coated film along alignment regulating forces which the
alignment regions contained in the alignment layer have, and
optionally subjecting the resultant to curing treatment to form a
retardation layer.
[0221] Referring to some of the drawings, a description is made
about a long-patterned-retardation-film producing apparatus used to
form such a long patterned retardation film of the invention. FIGS.
17 and 18 are each a schematic view illustrating an example of the
long-patterned-retardation-film producing apparatus. As illustrated
in each of FIGS. 17 and 18, a long-patterned-retardation-film
producing apparatus 40 has, besides the above-mentioned
long-patterned-alignment-film producing apparatus, an applicator 41
for applying a retardation-layer-forming coating solution
containing a rodlike compound having refractive index anisotropy
onto an alignment layer of a long patterned alignment film 10
formed by this producing apparatus, an aligning unit 42 for
aligning the rodlike compound contained in a coated film resulting
from the retardation-layer-forming coating solution along different
arranging directions of first and second alignment regions
contained in the alignment layer, and a curing unit 43 for
radiating ultraviolet rays to cure the rodlike compound, so as to
produce a long patterned retardation film 20.
[0222] The retardation-layer-forming coating solution in the
invention is usually composed of a rodlike compound and a solvent,
and may optionally a different compound. The solvent used in the
retardation-layer-forming coating solution is not particularly
limited as far as the solvent is a solvent in which the rodlike
compound can be dissolved in a desired concentration, and is
further a solvent which does not corrode the transparent film
substrate. Specifically, the solvent may be the same as described
in the item "A. Long Patterned Alignment Film".
[0223] The content by percentage of the rodlike compound in the
retardation-layer-forming coating solution is not particularly
limited as far as the content is within a range enabling the
viscosity of the retardation-layer-forming coating solution to be
set to a desired value in accordance with the method of applying
the retardation-layer-forming coating solution onto the transparent
film substrate, and others. In the invention, the content by
percentage is preferably from 5% by mass to 40% by mass, and more
preferably from 10% by mass to 30% by mass of the
retardation-layer-forming coating solution.
[0224] The different compound is not particularly limited as far as
the compound is a compound which does not damage the arrangement
order of the rodlike compound in the retardation layer used in the
invention. Examples of the different compound used in the invention
include a polymerization initiator, a polymerization inhibitor, a
plasticizer, a surfactant, and a silane coupling agent.
[0225] When the above-mentioned polymerizable liquid crystal
material is used as the rodlike compound, it is preferred to use,
as the different compound, a polymerization initiator or a
polymerization inhibitor.
[0226] The polymerization initiator used in the invention may be a
known ordinary compound, such as a benzophenone based compound.
When the polymerization initiator is used, a polymerization
initiating aid may be used together. Examples of the polymerization
initiating aid include tertiary amines such as triethanolamine and
methyldiethanolamine, and benzoic acid derivatives such as
2-dimethylaminoethylbenzoic acid, and ethyl
4-dimethylamidebenzoate. However, the aid is not limited
thereto.
[0227] The applying method for applying the
retardation-layer-forming coating solution onto the transparent
film substrate, and the method for drying the coated film resulting
from the retardation-layer-forming coating solution are not
particularly limited as far as the methods enable the coated film
to attain a desired planarity. These methods may be the same as
described in the item "A. Long Patterned Alignment Film".
[0228] In the invention, the method for arranging the rodlike
compound contained in the coated film, resulting from coating the
retardation-layer-forming coating solution onto the alignment
layer, along the alignment regulating forces, which the alignment
regions contained in the alignment layer have, is not particularly
limited as far as the method is a method capable of arranging the
rodlike compound into desired directions. The method may be an
ordinary method. When the rodlike compound is a liquid crystal
material, a method is used in which the coated film is heated to
the liquid-crystal-phase-forming temperature of the rodlike
compound, or higher.
[0229] When a polymerizable material is used as the rodlike
compound, the method for polymerizing the polymerizable material is
not particularly limited, and may be appropriately decided in
accordance with the kind of a polymerizable functional group which
the polymerizable material has.
[0230] 4. Usage
[0231] The long patterned retardation film of the invention may be
used for, for example, a patterned retardation film used in a
three-dimensional display device. The long patterned retardation
film can be in particular preferably used to form patterned
retardation films required to be easily mass-produced.
[0232] The invention is not limited to the above-mentioned
embodiments. The embodiments are exemplary. Thus, as far as any
embodiment that has substantially the same structure and produces
the same advantageous effects as the technical subject matter
recited in the claims of the invention is included in the technical
scope of the invention.
EXAMPLES
[0233] Hereinafter, the invention will be specifically described by
way of working examples thereof, and comparative examples.
Example 1
[0234] Prepared was a TAC (cellulose triacetate) film (FUJITAC.TM.,
manufactured by Fuji Film Corporation) having a thickness of 80
.mu.m. The film had, on a surface thereof, an AG (antiglare) film
(manufactured by Dai Nippon Printing Co., Ltd.) having a haze value
of 10 to 15 and obtained by dispersing transparent particles into a
transparent resin to coat. A coating solution containing PETA and a
photopolymerization initiator was painted onto the surface of the
TAC film that was opposite to the AG surface. The resultant coated
film was cured by UV to form an intermeddle layer (block layer)
having a thickness of 1 .mu.m. In this way, a roll-form original
film, 1 m in width and 2000 m in length, was prepared. The
apparatus illustrated in FIG. 6 was used to apply an
alignment-layer-forming coating solution containing a
photo-dimerization reaction type optical alignment material (trade
name: ROP-103, manufactured by Rolic Technologies Ltd.) as an
optical alignment material onto the intermediate layer side of the
original film, and then the resultant was dried to form an
alignment-layer-forming layer having a thickness of 0.1 .mu.m.
Polarized ultraviolet rays transmitted through a wire grid (their
polarization axis was along a direction having an angle of 45
degrees to the feeding direction of the film) were radiated
thereonto through a mask in which chromium was used to form, onto a
synthetic quartz piece, a pattern of stripes having a width of 500
.mu.m in a direction parallel to the feeding direction of the
original film. Next, polarized ultraviolet rays (their polarization
axis was along a direction having an angle of -45 degrees to the
feeding direction of the film) were radiated through not any mask
but a wire grid onto the workpiece to yield a long patterned
alignment film having an alignment layer.
[0235] A liquid crystal (licrivue (registered trade name)
RMS03-013C (trade name) manufactured by Merck KGaA) dissolved in a
solvent was painted onto the alignment layer of the long patterned
alignment film, which had been patterned, and the resultant was
dried (liquid crystal alignment). The workpiece was cooled to a
temperature close to room temperature, and then cured with
ultraviolet rays to form a long patterned retardation film having a
retardation layer having a thickness of 1 .mu.m.
[0236] The resultant long patterned retardation film was observed
through crossed Nicol state polarizing plates. As a result, it was
verified through a bright and dark pattern thereof that the
alignment layer was patterned.
Example 2
[0237] A long patterned retardation film was formed in the same way
as in Example 1 except that the apparatus illustrated in FIG. 7 was
used to radiate, in the second polarized-ultraviolet-ray-radiation,
polarized ultraviolet rays through a mask as obtained by changing
the openings and the light-shielding part in the mask used in the
first polarized-ultraviolet-ray-radiation from each other and that
a long patterned alignment film having an alignment layer was
formed. The resultant was observed through crossed Nicol state
polarizing plates. As a result, substantially the same result was
obtained.
Example 3
[0238] A long patterned retardation film was formed in the same way
as in Example 1 except that the apparatus illustrated in FIG. 17
was used to form this long patterned retardation film continuously
from the original film. The resultant was observed through crossed
Nicol state polarizing plates. As a result, substantially the same
result was obtained.
Example 4
[0239] A long patterned retardation film was formed in the same way
as in Example 3 except that the apparatus illustrated in FIG. 18
was used to form this long patterned retardation film continuously
from the original film. The resultant was observed through crossed
Nicol state polarizing plates. As a result, substantially the same
result was obtained.
REFERENCE SIGNS LIST
[0240] 1 . . . Transparent film substrate [0241] 2' . . .
Alignment-layer-forming layer [0242] 2 . . . Alignment layer [0243]
2a . . . First alignment regions [0244] 2b . . . Second alignment
regions [0245] 2c . . . Non-alignment regions [0246] 3 . . .
Long-alignment-film-forming film [0247] 4 . . . Retardation layer
[0248] 4a . . . First retardation regions [0249] 4b . . . Second
retardation regions [0250] 4c . . . Buffer regions [0251] 5 . . .
Antireflective layer or antiglare layer [0252] 6 . . . Adhesive
layer [0253] 7 . . . Separator [0254] 10 . . . Long patterned
alignment film [0255] 20 . . . Long patterned retardation film
* * * * *